Vibrational spectra of the pseudotrigonal bipyramidal tetrafluorides SF 4 and CIF 4+

Abstract

The Raman spectra of gaseous, liquid and solid SF 4 have been re-examined. Polarization measurements allow the unambiguous identification of the A 1 modes. The i.r. spectrum of SF 4 isolated in N 2 matrix has been recorded and 32S 34S isotopic shifts have been measured for several fundamentals. The matrix isolation study indicates that the 353 cm −1 absorption consists of two fundamentals, thus providing the hitherto missing ninth fundamental of SF 4. Complete assignments are given for SF 4 and are supported by force field and mean amplitudes of vibration computations. The results from the vibrational analysis support an intramolecular Berry-type exchange mechanism for SF 4. Raman polarization data have also been obtained for CIF 4 +SbF 6 − in HF solution and revised assignments and force field values are given for CIF 4 +.